"Instant payments definition". www.ecb.europa.eu. European Central Bank. 2017. Archived from the original on September 9, 2018. Retrieved September 8, 2018.
frb.org
app.ny.frb.org
"What is a Payment System?"(PDF). Federal Reserve Bank of New York. October 13, 2000. Archived from the original(PDF) on 21 October 2012. Retrieved 23 July 2015.
"What is a Payment System?"(PDF). Federal Reserve Bank of New York. October 13, 2000. Archived from the original(PDF) on 21 October 2012. Retrieved 23 July 2015.
"Instant payments definition". www.ecb.europa.eu. European Central Bank. 2017. Archived from the original on September 9, 2018. Retrieved September 8, 2018.